1. SeaWiFS-based chlorophyll in selekt Chl [mg m -3 ] Sub-decadal oceanic oscillations regulate the north-eastern Atlantic shelf ecosystems Hjálmar Hátún, Payne, M., Sandø, A. and others... Santander, 2011 Blue whiting Sub-decadal oceanic oscillations and blue whiting recruitment

2. Outline The subpolar gyre – marine climate link and blue whiting stock dynamics Can we predict recruitment? – some new ideas on the sub-decadal variability.

3. Subtropical Gyre Subpolar Gyre Labrador Sea convection (Hatun et al., Science 2005) 1. The Subpolar Gyre and the marine climate

4. R I Salinity in the Irminger Current (obs.) Salinity at Rockall (obs.) Gyre index (GI) Record high T and S 1. The Subpolar Gyre and the marine climate Weak. Strong

5. Simulated temperature Cold Warm 1. The Subpolar Gyre and the marine climate Large mid-1990s changes!

6. Blue whiting Blue whiting: Spawning-feeding distributions/migrations Feeding Spawning Mackerel Herring

7. Stor endringer i kolmule bestanden Largest fishery in the North Atlantic! A threefold blue whiting stock size increase SST (in Rockall Areal) Stock size (<- shifted 3 years)

8. Warm (1998-2003) Cold (1990-1996) Spatial Shift (Blue whiting catches – all nations) 1997 Spawning distribution: (Hátún et al. 2009, CJFAS) Post-spawning migration: (Hátún et al. 2009, PIO)

9. So what about blue whiting recruitment?

10. Need to understand the processes (Payne et al., 2011, In Press) North Atlantic Sub-polar gyre Recruitment Gyre index and recruitment not significantly correlated Atmospheric forcing

11. Wind stress curl UK Green- land Anticyclonic (Curl <0) Wind stress (ws) - arrows (NCAR/NCEP) Curl (ws) [N/m ] 2 0 Cyclonic (Curl >0) 2. Atmosphere-gyre details

12. WSC = 0 Subtropical Gyre Subpolar Gyre 2. Atmosphere-gyre details

13. Subpolar Gyre ”Inter-gyre region” ’Window’ 2. Atmosphere-gyre details WSC = 0 Subtropical Gyre

14. ’Navidad’ ”Inter-gyre region” Subpolar Gyre 2. Atmosphere-gyre details

15. Recruitment and wind stress curl 2. Recruitment Spain R Recruitment Vs. WSC

16. Recruitment and wind stress curl

17. Northward transport Improved Recruitment?

18. Sea surface height and marine climate Warmer 3. Monitoring with altimetry

19. Gyre Mode Spatial pattern (Updated from Hakkinen and Rhines, 2004) 3. Monitoring with altimetry Time series (gyre index)

20. Transport anomalies of source waters Western source Eastern source 3. Monitoring with altimetry ~ 7 Sv (Pingree, 2002)

21. An along-Continental Slope perspective (Data availability) Decompose onto a S-axis Porcupine (Hátún et al. 2009, CJFAS) 2. Hydrographic Pulses

22. Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses Salinity

23. Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses Salinity, currents Weaker NAC

24. Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses A new boom? Salinity, currents and recruitment

25. So is the recruitment predictable? Not with certainty - But certainly not if the marine climate is ignored I ’predict’ that the 2009 year-class will be strong

27. 3. Monitoring with altimetry Transport anomalies of source waters

28. 3. Monitoring with altimetry Transport anomalies of source waters and blue whiting recruitment

29. Salt-pulses and blue whiting recruitment 2. Recruitment Porcupine Shetland

30. So what about recruitment? Bad recruitmentGood recruitment (Hátún et al., 2009, CJFAS)